Oxyalkylene polymers having at least one reactive silicon group in the molecule are well known. The polymers are curable at room temperature yielding a rubbery substance and are used as a sealant and the like.
Of these polymers, polyoxypropylene having terminal methoxysilyl groups has already been industrially produced (trade name: MS Polymer of Kanegafuchi Chemical Industry Co., Ltd.). The cured oxyalkylene polymers having a reactive silicon functional group are rubbery substances preferably free of surface tack, and this property is especially important where the polymers are used as a sealant. This is because dust or dirt is apt to adhere to the surface where the surface is tacky. The drawback of the oxyalkylene polymers having a reactive silicon group, however, is that these polymers can produce cured substances having a tacky surface.